public static void Main()
{
    List<T_Info_PriorApplys> list = new List<T_Info_PriorApplys>();
    list.Add(new T_Info_PriorApplys() { });
    list.Add(new T_Info_PriorApplys() { });
    list.ForEach(item => item.ApplyNo = "testNo" + list.IndexOf(item));
    list.ForEach(p =>
    {
        if (p.ApplyNo == "testNo0")
        {
            list.Remove(p);
            list.Insert(0, new T_Info_PriorApplys { ApplyNo = "NewNo0-1" });
            list.Add(new T_Info_PriorApplys { ApplyNo = "NewNo0-2" });
        }

    });


    list.ForEach(item => Console.WriteLine(item.ApplyNo));
    Console.Read();
}

/* 运行结果：
NewNo0-1
testNo1
NewNo0-2
*/

list.ForEach(p =>
{
            list.Remove(p);
            list.Insert(0, new T_Info_PriorApplys { ApplyNo = "NewNo0-1" });
            list.Add(new T_Info_PriorApplys { ApplyNo = "NewNo0-2" });
});